Passenger seats of automobiles or trains, various kinds of sofas, office chairs and the like are often formed by attaching a skin material such as fiber fabric, or natural or synthetic leather to a surface of a cushion body (foam body) molded in a predetermined shape by using foam resin. The cushion body used in these various seats sometimes has a curved surface composed of a concave-convex shape satisfying human engineering factors in order to maintain a seating posture which provides no fatigue despite long-hour seating.
Furthermore, in a case that the skin material is attached to the surface of the cushion body, a method of covering and fixing the skin material to the surface of the obtained cushion body after molding the cushion body in a desired shape, is often employed. Particularly in this case, a molded surface fastener having a plurality of hook-shaped engaging elements is generally used as a means of fixing the surface of the cushion body and a rear surface of the skin material.
The molded surface fastener is formed, wherein a plurality of hook-shaped, male engaging elements is disposed on one surface of a base portion made of thermoplastic resin. Such a molded surface fastener is integrated to the surface of the cushion body such that the engaging elements are exposed by foam molding of the cushion body with a molding die in a state that the molded surface fastener is attached to a cavity surface of the molding die. On the other hand, a plurality of loop-shaped engaging elements (hereinafter loop-shaped engaging elements are referred to as loops) which can be fastened to the engaging elements of the molded surface fastener is provided on the rear surface of the skin material that covers the cushion body.
After the cushion body to which the molded surface fastener is integrated is covered with the skin material, the loops disposed on the rear surface of the skin material are pressed against the molded surface fastener disposed on the front surface of the cushion body, whereby the loops of the skin material are engaged with the hook-shaped engaging elements of the molded surface fastener, and the skin material is fastened to the molded surface fastener. In this manner, the skin material is easily fixed to the surface of the cushion body along a concave-convex shape of the front surface, which prevents the skin material from floating up from the cushion body.
As a means of attaching the molded surface fastener to the cavity surface of the foam molding die when foam molding the cushion body, it is conventionally carried out that a magnet is buried under a fastener attaching surface of the molding die, while a magnetic material attracted to magnetically by the magnet of the molding die is attached to the molded surface fastener, or the magnetic material is contained partially in the molded surface fastener.
As a means of attaching the magnetic material to the molded surface fastener, for example, it is known that a monofilament containing a magnetic material is fixed to a base portion of the molded surface fastener, a film containing a magnetic material is laminated on a base portion of the molded surface fastener, and that a magnetic material is applied to a flat plate-shaped base portion of the molded surface fastener, and others. In International Publication 2012/025980 (Patent Document 1), for example, a molded surface fastener in which a monofilament containing a magnetic material is fixed to a base portion is disclosed.
The molded surface fastener described in Patent Document 1 includes a thin plate-shaped base portion which is long in a front and rear direction, right and left barrier portions disposed at right and left side edge portions of the base portion and standing on the base portion along a length direction in order to prevent a foam resin material of a cushion body from intruding, a plurality of hook-shaped engaging elements disposed between the right and left barrier portions, a magnetic body holding portion protruded from the base portion on an inner side of the barrier portions, a lateral wall portion disposed along a width direction, and a fin piece portion extended outward in the width direction from right and left side edges of the base portion. Furthermore, a linear magnetic body formed of a monofilament containing magnetic particles is integrally fixed to the base portion along a length direction so as to be held by the magnetic body holding portion.
On the other hand, in a case that a magnetic material is partially contained in a molded surface fastener, a method of manufacturing the molded surface fastener by a two color molding using a synthetic resin material containing magnetic materials (magnetic particles) and a synthetic resin material containing no magnetic materials is generally employed, for example. The molded surface fastener manufactured by such a two color molding is disclosed in International Publication 2003/030672 (Patent Document 2).
In the Patent Document 2, a molded surface fastener 90 shown in FIG. 19 and FIG. 20 is described. The molded surface fastener 90 according to Patent Document 2 includes a thin plate-shaped base portion 91 which is long in a front and rear direction and a plurality of hook-shaped engaging elements 92 standing on an upper surface of the base portion 91. Furthermore, in a central part of the base portion 91 in a width direction, a plurality of magnetic projecting portions 93 containing magnetic particles is provided in a line along a length direction. A plurality of engaging elements 92 is disposed to be aligned on both right and left sides of these lining magnetic projecting portions 93.
Each of the magnetic projecting portions 93 is projected on the upper surface of the base portion 91 in a rectangular parallelopiped shape. Valley portions are provided between the magnetic projecting portions 93 adjacent in the length direction. In this case, the magnetic particles are mixed into synthetic resin at a predetermined ratio within each of the magnetic projecting portions 93 and supporting portions disposed under each of the magnetic projecting portions 93 on the base portion 91.
The molded surface fastener 90 according to Patent Document 2 containing the magnetic particles in this way, is moved closer to a fastener attaching surface of the molding die in which a magnet is arranged, for example, thereby a magnetic force is generated between the magnet of the molding die and the magnetic particles of the molded surface fastener 90. Thus, the molded surface fastener 90 can be attracted to the fastener attaching surface of the molding die magnetically and can be adhered and fixed to the fastener attaching surface. Afterwards, a cushion body to which the molded surface fastener 90 is integrated on a front surface is manufactured by foam molding of the cushion body in the molding die in a state that the molded surface fastener 90 is fixed to the fastener attaching surface of the molding die.
Furthermore, in Patent Document 2, a molded surface fastener wherein hook-shaped engaging elements containing magnetic particles instead of the magnetic projecting portions 93 shown in FIG. 19 and FIG. 20 are disposed in two lines along a length direction as a modification example of the molded surface fastener. In this case, the magnetic particles are contained within the engaging elements and a portion of a base portion supporting the engaging elements.
Since such a molded surface fastener as mentioned above is often required to have a high engaging strength when engaging with loop-shaped female engaging elements of skin materials or the like, a means of enhancing the engaging strength with respect to the loops has been considered for a long time. For example, a molded surface fastener wherein an engaging strength (disengaging strength) with respect to loops is enhanced by making it easier to catch the loops with hook-shaped engaging elements is disclosed in Japanese Patent Publication No. 8-56712 (Patent Document 3).
In the molded surface fastener according to Patent Document 3, a plurality of hook-shaped engaging elements stands on an upper surface of a flat plate-shaped base portion. In this case, the engaging elements align along a length direction to form an element row. Such a plurality of element rows formed along the length direction is disposed on the base portion in a width direction at a predetermined interval.
In the molded surface fastener according to Patent Document 3, a plurality of guide members distributing and guiding the loops to be engaged toward the hook-shaped engaging elements is provided between the element rows adjacent in the width direction. Each of the guide members of Patent Document 3 protrudes from the flat plate-shaped base portion in a medial position of two element rows adjacent in the width direction, and right and left side surfaces of each of the guide members are formed to be curved surfaces in which a width dimension of each of the guide members gradually decreases as getting closer to the base portion.
Since the molded surface fastener according to Patent Document 3 is provided with the guide members as mentioned above, when, for example, a female surface fastener having a plurality of loops is engaged with the molded surface fastener, the loops to be inserted between the adjacent element rows of the molded surface fastener can be guided with the guiding members toward the hook-shaped engaging elements and engaged. As a result, the hook-shaped engaging elements are able to catch and engage as many loops as possible, thereby an engaging strength (disengaging strength) with respect to the loops of the molded surface fastener can be enhanced. Furthermore, a molded surface fastener in which a guide member is disposed in a medial position of front and rear hook-shaped engaging elements is described in Patent Document 3 as a modification example.